Returning
by Scout-n-Demond
Summary: Things have changed since the human left the Underground. The Monarchy has collapsed and everyone is left to defend for themselves. In the midst of everything, Sans decides it's finally time to make a change and find a way to get Dr. Gaster back, along with the help of Alphys.
1. Chapter 1

**Warnings** : Major spoilers for the Pacifist run and one of the Neutral endings. Mentions of suicidal ideation.

Undyne was dead. Queen Toriel had stepped down from her position only weeks after having taken it back. The Underground was in a state of uneasy anarchy. Each province "governed" itself, certain monsters stepping up to keep what little peace they could. Alphys just couldn't understand how the actions of a human child could cause such discourse in the monsters' homeland; how the death of only a few people could destroy everyone's perceptions to the point of overthrowing their kind queen.

While initially Alphys had not known of her longtime crush's death, she did go back over all of the footage she had of the human and watched as they killed Undyne. While a majority of the Underground did not know of the captain of the Royal Guard's death, most at least suspected that her going "missing" had something to do with the human. It certainly did not help that after the human disappeared from the Underground, King Asgore's dusty remains were found before the Barrier. Everyone was able to make the connection between the king's death and the human's disappearance, so why not put two and two together and conclude that the human had killed Undyne as well?

Despair had been Alphys' life for the weeks leading up to the "overthrowing" of the queen after the human fiasco. Undyne, one of her closest friends and crush; and Asgore, a mentor, someone whom she had looked up to, and yet another crush; both were killed by the child whom Alphys had only wanted to support on their journey. All she really had left was Mettaton, and he had been so wrapped up in trying to be both a star and be there for his cousin Napstablook, she was certain that she never even crossed the robot's mind.

The only solace she could find these days was that she still had her lab. Seeing as the Underground's monarchy was no more, she was no longer considered the Royal Scientist, and in fact didn't even have a job anymore. With the Underground being run by something akin to anarchism, there was always the fear that someone would try to take her home and workspace from her. Thankfully, it appeared that being a close friend to the Underground's only celebrity had some perks. While Mettaton didn't seem to have the time of day for her anymore, he must have been doing something to keep any rogue monsters from taking over her lab. With the power and influence that Mettaton had over the populace, it was a wonder he hadn't simply stepped up to take over for the fallen monarchy. That of course was a question for another day. Right now, Alphys didn't really have the will or energy to even want to think about something like that happening.

She sighed, curling in on herself as she grabbed another handful of chips from the bag she held. Ever since the human had left and the Underground's monarchy had fallen to shambles, she had gone back and forth between wanting to try and help the populace, or to just end her life and be done with it. No one would miss her, and she had been pondering on the idea of taking her life for over a good year now. All she had done was cause so many families pain, disfiguring their relatives and leaving no one with any answers whatsoever. How could she possibly help the Underground's situation when she couldn't even save the monsters from the Determination experiments? Surely, she would just make the entire situation worse than it already was.

There was a quiet sniffing heard from the other side of the room, and she looked over to see the Endogeny Amalgamate bounding up beside her, its numerous tails wagging in sync. Feeding time had been only an hour ago, so that could mean only one thing: it wanted to play. Of course, she was in no mood to play at the moment, wanting nothing more than to sit and contemplate everything that had been going on. Then again, perhaps a distraction was what she needed. This particular Amalgamate had stopped her from killing herself before, reminding her that she still had responsibility over the monsters living in her lab.

The Endogeny shoved three of its front paws onto her lap, the slime from its face dripping down onto her lab coat. It was beginning to bounce in excitement, the slime being flung about the room as the Amalgamate continued trying to get its caretaker to play with it.

"Okay, fine," Alphys murmured, only to repeat the statement as the Endogeny continued its excited bouncing and slobbering.

Noticing its small, yellow caretaker rising from her seat, the Endogeny backed up, running around the room in excited circles. Alphys couldn't stop herself from smiling, seeing its boundless energy and how content it appeared to be. Her mood darkened however as it also occurred to her that not all of the Amalgamates were as content as the Endogeny. Nevertheless, the monster before her was determined to be played with, and the mood of the scientist before it would not deter it. It ran from the small office, though experience told Alphys that it was simply looking for one of its many toys that were scattered around the lab.

She left her office, figuring that its moderate size would not be enough for the Endogeny. Entering the lab's resting room, she saw that yes indeed, the Endogeny was searching for what toy it wanted to play with, sniffing under every bed and leaving behind a trail of slobber as it went. Originally, seeing the amount of slime that the Endogeny emitted whenever it got excited upset her, as she disliked cleaning up after it once it calmed down. Now, she still disliked cleaning up after the Amalgamate, but she had learned to deal with it. As long as it was happy and content, she could feel better about herself, at least in the slightest.

The sound of rapid squeaking brought her back to attention, informing her that the Endogeny had finally found what it was looking for. The monster ran up to her, squeaking the large ball in its mouth with every step it took. To no one's surprise, it wanted to play fetch. That would explain its near constant bouncing and running around up until that point. Alphys gave another faint smile to the monster before her, taking the (already completely slobbered) ball and giving it a good toss across the dim room. She watched as slime flew from the ball, landing on any bed it sailed over. The Endogeny didn't seem to care about this one bit, bounding over the very same beds in its journey to catch the ball.

It brought the ball back to her, sometimes playfully staying out of her reach so that she couldn't take the ball back from it. Then she would throw it back across the room and the Endogeny would retrieve it once again. They continued like this for some time, the Endogeny having more energy than any other of the Amalgamates. Alphys could admit that she did enjoy these times, actually feeling needed for once rather than being a burden. She could feel somewhat like how she used to be before everything went to hell.

The Endogeny brought back the ball, dropping it at her feet, bouncing back and forth as it waited for her to throw it once more. Her mood having been soured once again by her own thoughts, she picked up the ball and threw it, though it only went half as far as it had all the other times. Once again, the Endogeny did not appear to care one bit about this, leaping after the ball as if it had still flown all the way across the room.

"Enjoying yourself?" a voice sounded from behind her.

Alphys nearly screamed, whipping around faster than she thought possible. That certainly was _not_ any of the voices that she was familiar with from the Amalgamates.

" _Sans_?" She did her best to keep her voice down, though it did no good. Her heart was racing, sweat quickly forming along her brow.

"Hey," he winked. "Sorry, did I give you a fright?"

"Yes! I-I wasn't," she paused, "I wasn't expecting a-anyone to show up here. H-How did you get down here?" She inwardly cursed herself as her nervous stutter returned. It seemed she could never get through any conversations without it appearing at least once.

"Let's just say I took a shortcut," he replied, that ever apparent grin plastered on his face. Alphys vaguely wondered if he ever went without it, recalling that she had never seen him come even close to frowning before. Her thoughts were interrupted by something shoving against her arm and whining before they could go any further.

She pat the Endogeny's head, letting loose a nervous giggle. "Hey, I d-don't think we can play a-anymore right now. I've g-got a guest, see?" The Amalgamate simply whined in the face of this revelation. "Oh c-come on, why don't you find Reaper Bird? It u-usually l-likes playing with you," she continued, glancing back over at the stocky skeleton patiently waiting nearby.

The Endogeny sat in dejection in front of its abandoned ball, very little slime being produced from its mouth any longer. While Alphys felt bad about not being able to play with it anymore, she needed to tend to her guest. Moreover, she needed to figure out why her guest was even here in the first place.

She touched Sans' arm, walking towards the hall. "Here, we c-can talk in my office."

He followed only a few steps behind her, which admittedly made her nervous. Trying to break the ever growing anxious feeling he was giving her, she attempted to strike up a conversation with him.

"S-So, um, what are you doing here?" she stuttered. "I mean, n-no one ever c-comes here anymore, since I'm not really the Royal Scientist anymore, and…" she trailed off, realizing that if she kept going she would begin to ramble.

Under normal circumstances, she suspected that Sans would have chuckled over her nervousness, but today he was remaining quiet. While she didn't know Sans very well, she did remember certain instances where he got like this. Or did she? Now she was questioning herself. When had Sans ever been like this?

"I need your help," he told her after what felt like an eternity. In reality, it had only taken until they had reached her office a few paces from the rest room, but she couldn't help but let her anxiety get the better of her.

"O-Okay," she murmured, opening the door to her office and stepping inside. "Um, have a seat," she continued, gesturing towards an empty chair beside her desk. Why it wasn't in front of her desk like usual was beyond her, though she figured that one of the Amalgamates had simply bumped it aside while going through the room.

Taking her own seat at her desk, she noticed that Sans appeared to have no intentions of sitting down, staring at her, hands in his pockets as always. Without even thinking, she stood back up, feeling much more uncomfortable around the skeleton than she ever remembered being.

"S-So, w-what do you w-want help with?" She swore at herself, upset over the worsening of her stutter.

Sans closed his eyes and sighed before opening only his left eye socket.

"Do you remember a monster called Dr. Gaster?" was all he asked.

The name instantly rang a bell. For a moment she was going to respond to his question, but as soon as it came, it was gone. No, she had definitely never heard of anyone named Dr. Gaster. Apparently Sans had seen the sudden confusion on her face, as he gave a shrug with a light shake of his head.

"Looks like I really _am_ the only one," he muttered to himself. "Listen," he spoke up, "I'm going to tell you some things that you probably won't understand right away. So just bear with me, okay?"

Unable to voice anything past her utter confusion, Alphys nodded back to him.

"Can you tell me anything about the Royal Scientist that Asgore hired before you?" was his next question.

Well, this was something she could certainly answer. "Of course, he made the Core. He was a brilliant monster! It took King Asgore ages to find anyone who could replace him!"

Sans' grin widened slightly. "Do you remember anything else about him?"

At that, Alphys found herself at a loss. No, she didn't know anything else about him. Nothing whatsoever.

"Didn't think so," he gave her another wink. "This monster, his name was W. D. Gaster. He was Asgore's Royal Scientist and advisor for ages."

Alphys paused for quite a while, Sans patiently giving her the time to ponder over this new information. It was bothering her how every time she thought she knew something about this Dr. Gaster, the information was immediately lost. How could she not remember the name of the man who preceded her? Who advised the king and created the Core? Why had she never even questioned it until now?

"S-Sans, I'm sorry, b-but h-how do you know this?" she questioned.

"Well, Dr. Gaster was my dad, that's how. You and I worked as his interns for most of his projects." His grin widened even further at Alphys' surprised look.

"You're kidding. I-I would r-remember this, wouldn't I?" She took a step back, sweat dripping down her brow, her hands slick in the substance. Thoughts—memories?—kept coming to her, only to disappear as quickly as they came.

"Apparently not. You're still with me on all of this, right?"

"O-Of course!" she blurted out, only to cover her mouth with her sweat drenched hands shortly afterwards, her face reddening at her outburst.

At this, Sans' face finally took on a look of concern, his grin softening. "Hey, you should really take a seat. You look like you're gonna pass out."

"Oh, uh, yeah. Right," she stumbled, plopping down into her desk chair. "S-So, you and I; w-we were w-working with your dad, the m-monster who was the Royal Scientist before me."

"Yeah," Sans responded, stepping up to the desk. As he approached, he pulled a small device out of his jacket pocket. As he set it down next to Alphys' computer, she noticed that it was a flash drive. "We were working on manipulating the timelines."

Alphys caught herself eying the flash drive, quickly bringing her gaze back up to Sans. "Timelines? Y-You mean like time travel? Stuff like that?"

"Yeah, sorta like that." He indicated towards the flash drive. "Plug that into your computer. There's some information on there I want you to see."

Sitting back down in her desk chair, Alphys grabbed the flash drive, the small device slipping through her fingers as she fumbled with it.

As she proceeded to plug it into her computer, Sans continued, "You see, after finishing his work on the Core, Gaster found out about the existence of these timelines. He was taking readings from the Core so he could regulate it, but every now and then these strange readings would always filter through."

As the flash drive's information popped up on her computer screen, Sans came around the desk.

"Okay, open that folder," he instructed, pointing at a folder labeled _CORE Readings_.

Alphys did as she was told, opening the files as Sans continued to point them out. Eventually, a whole slew of graphs were opened upon her screen, all of them labeled as various readings from the Core, all taken years before she ever took up the mantle as Royal Scientist. As Sans had indicated, each graph had at least one or more spikes and dips during the course of the readings.

"So, what does all of this mean?" she questioned, nervousness all but gone. _This_ was something she could work with.

"I don't know how he did it, honestly," Sans responded. "I've searched through what information I have left from him, but nothing pinpoints just how he was able to connect these spikes with changes in the timelines."

"So these jumps here," she pointed to a particularly large spike, "are all changes in our timeline?"

"That's what Gaster found out, yeah. He built an entire machine just based around finding jumps within the timeline and recording them. I have those readings on another folder here," he pointed to a different area of the flash drive's contents.

As Alphys brought the readings in question up, she voiced her first confusion, "So what was causing these jumps? Was something going back in time? Like, changing things?"

"That's what we were trying to figure out," Sans answered. "Gaster was never really able to figure out what this anomaly was, but he started basing all of his research entirely on finding it. Look here," he motioned towards one of the new graphs, which had twice as many jumps in the readings as any of the others. "This was taken only a few days after Prince Asriel and Chara died. Before this, there were hardly any jumps in the timelines at all, but here they just begin to spike. All of the graphs after this are pretty tame, but the spikes in the readings are still greater than before the princes died. Gaster hypothesized that the anomaly was trying to bring them both back to life to prevent the Royal Family from falling apart, but obviously the anomaly failed."

He sighed before continuing on, "Gaster never found out if that was what the anomaly actually wanted or not. He tried to figure out if perhaps it was the king or queen who were causing the jumps, but I don't think his results were ever conclusive. Nothing really lined up." He guided Alphys over to some readings taken only a couple years after the first handful. It appeared that the spikes had indeed subsided back to their usual amounts. Then the readings stopped all together until many years later.

"So, what happened here?" Alphys asked, gesturing towards the gap.

"That's when Gaster fell into the Core."

"He _what_?" she barely gasped out. Her chair had been swiveled around so she could fully face the skeleton behind her.

Sans shrugged once more, looking oddly nonchalant for someone who had just dropped a bombshell. "We were getting nowhere in our research. Gaster had hit a dead-end. So he started working on a different project. He figured that if he couldn't find the anomaly messing with our timeline, then he would replicate it instead. So he started working on a time machine."

"And he had enough information to be able to accomplish this?" Alphys asked, incredulous.

"Gaster was a brilliant monster, you know. He had been running so many different experiments on the Core that he stopped coming home anymore." The expression on his face deflated after this. "What's worse, is I don't even have any of the results from the experiments he conducted, outside of what I helped on. If you look here," gesturing towards a lone folder labeled simply _CORE_ , "I have some of his hypotheses, and there's some observations from me that I don't even remember making."

Alphys looked over the unfinished lab reports before her, skimming over numerous hypotheses and observations that made very little sense to her without any of the actual results and procedures to go with them.

"I think Gaster figured, since he got his initial readings of the anomaly from the Core, then perhaps he could utilize the Core to help him with his time machine, or whatever it was he was trying to build."

After this, Sans stepped back, shoving his hands back in his jacket pockets. Alphys turned back around to look at him.

"I don't really remember much. Some days I remember more than usual; some days I remember less, but I do remember that I was there when Gaster fell into the Core." He looked off to the side. Alphys noticed the sweat forming along the top of his skull. "Gaster, he was trying to do some experiment. I don't know what, but something happened; something went wrong. I wish I could remember what was going on, but either way, he fell in." One hand was pulled from its pocket to wipe the sweat from his brow. "And I guess it proved one of his hypotheses, at least. After he fell into the Core, he was gone. I think he got lost in the timelines, and now no one can remember who he is. Everything about him was erased. There're monsters mentioned in some of his lab reports that I don't remember meeting in my entire life, and I think those monsters got erased along with him. Do you get what I'm trying to say?"

Alphys nodded. "I think I do. He fell into the Core, which is somehow related to our timeline, and that essentially erased him from existence. Monsters he worked with and most of his research ended up going along with him. Am I right?"

"Yeah, pretty much, but I'm sure you noticed what's wrong with this, right?"

"Well, if people he had any relation to ended up disappearing, the question is, how are you and Papyrus still here, correct?"

"Exactly. That's the major problem I haven't been able to figure out. It'd make sense if Gaster's sons disappeared with him, wouldn't it?"

"You say I worked with you guys on this too, right? So then I shouldn't exist either."

"Right. So I had a hypothesis of my own." At this, Sans walked back up to Alphys' computer, opening up one final folder labeled _Untitled_. It appeared to be the beginning of a lab report. "If you, me, and Papyrus all still exist, then there's obviously still a trace of Gaster left around. If he hasn't been completely erased from our timeline, then it should be possible to retrieve him."

Alphys read over the information Sans had written, intrigued with where he was going with this. "Is that why you're here? You want me to help you bring Dr. Gaster back?"

"Yeah. Originally, I thought that it wouldn't be possible to bring him back. All of my experiments, everything I tried; nothing worked. I wasn't getting anywhere, and after all of the timelines began resetting so often, I started losing all of my motivation."

One part of that statement caught Alphys' interest. "Why would the timelines resetting cause you any problems?"

She got a light chuckle out of him for that. "I forgot to tell you, didn't I? I didn't come out of Gaster's accident unaffected. After he fell into the Core, I could remember all of the resets." His eye sockets darkened as Alphys' own eyes widened. "I didn't notice it at first; I just thought I was having some really vivid dreams, but then I finally realized what was going on. It was Papyrus. Every time we would reset for a while, it reset back to a time where Papyrus woke me up, telling me Undyne was going to start giving him cooking lessons. After the fifth time it happened, it finally occurred to me that I had already been told that before. Numerous times."

He made one final gesture, back toward the initial timeline readings. Alphys' attention was directed towards the readings made at the end of the large gap. "I turned Gaster's machine back on and took some readings. Every time I had one of those moments, there would be a jump in the readings. That's when I finally figured out that I wasn't forgetting any of the resets anymore." He stepped back from the computer again, turning Alphys' attention back to him. "I think that's why I'm the only person who remembers anything about Gaster."

"Interesting," Alphys mumbled, "and you can't come up with any explanation for this?"

"The only thing I can think of is that Gaster's accident in the Core caused it. It makes sense if the Core is related to the timelines like he thought."

With that said, Alphys stood from her chair, moving to the front of her desk so that she could begin a light pace. Having all of this information dropped on her at once was making her antsy, and she wasn't sure what to think yet. Sans had the information to prove himself all on that flash drive, and she trusted him enough to know that he wasn't pulling her leg. While he was a bit of a prankster, this was far too intricate for him. Too much effort was put into this. Sans himself had just admitted that he didn't have the motivation to put something like this together. Besides, if all of this was true, then wouldn't that explain her own instances of déjà vu, or the times where she thought she remembered something, only for the memory of it to completely disappear?

"So," she stopped pacing, looking at the skeleton standing behind her desk, "why do you want to save Gaster now? Why are you trying again after all of this time?"

"The timelines stopped jumping," was his simple response.

That gave her a pause. "They did?"

"Yeah, I have the graph on the drive here, but pretty much ever since that human left the Underground, there hasn't been a single reset. The longest we've ever gone before without a reset is a few months. It's been over a year and we still haven't had a reset. I thought perhaps it was time to try and get Gaster back before that reset actually happens."

"You're actually going to risk this? I mean, if it's already been so long since the last reset, then either they've stopped entirely or we're about to get one very soon. There's a fifty-fifty chance that all of our work could just be erased."

"That's why I need to risk this," was Sans' response as he came back around the desk. "If we can rescue Gaster now, then he should remain as a constant in our timeline. His time lost in the Core might have affected him the same as I've been affected, and he'll likely remember everything. We could use his help to find this anomaly once and for all and stop the timelines from resetting."

"You have a point, but where do we start?" she asked.

"Well," he proceeded, "I was able to make some progress on my own, and I've jotted down everything that I could remember from my previous experiments in other timelines. I figured that if we worked together with this, we could make enough progress to get Gaster back for good, or to at least get me enough information before the timeline resets again."

He went silent, deep in thought. As Alphys was about to ask him another question, he spoke once more. "Alphys, I need to know now if you're going to help me with this. I don't think we have much time to get Gaster back. We have a chance to repair our timeline and stop both the anomaly and that human from destroying everything. If you're not going to take this seriously and give this your full attention, then there's no point in us even trying. So are you going to agree to helping me out here?"

Alphys didn't even have to think about it. She gave a single nod of her head. "Of course. I'll help you. I…" she trailed off. "I don't have anything else to do besides help you."

Sans' face remained somber. "So you wouldn't mind holing yourself up down here with me and working on this nonstop? Because, that's what we're going to have to do. We don't have the time to take any breaks. A reset could happen at any moment."

"Sans," she looked away, "I don't have anywhere else to go. There's nothing else for me to do." She smiled lightly. "I think this might actually give me some sort of purpose. You know, saving the timeline from some enemy? It's like that one anime Undyne and I used to watch before she, you know." She didn't know if Sans thought Undyne had gone missing or was killed, but she figured he was smart enough to have been able to figure it out.

"Then we should get started," he moved on, ignoring her comment. "We can go back over all of the information I have right now. Maybe we could go over some of the files you have down here, too? Something might not have gotten erased that Gaster worked on. It could help us out."

"Yes, we can look over everything, but I don't know if we'll find much." She paused, a thought occurring to her. "Sans, does Papyrus know about any of this? Have you told him anything?"

"No, he doesn't know anything. We're not going to be telling him anything, either. It's easier if he doesn't get involved." He sighed, putting a hand to his face. "When I said that we weren't going to be taking any breaks, I meant it. I don't think I'm ever going to see Papyrus again in this timeline. I can't afford the time we would lose by going to Snowdin to see him, or talking to him on the phone."

At this, Sans pulled his cell phone out of his pocket, setting it down on Alphys' desk. She eyed the phone as Sans brought his attention back to her.

"It's dead, and I won't be charging it back up. I suggest you do the same with yours. We need to be committed to this, right?" He winked, though his somber look remained. "I haven't had the motivation to do anything like this in so long, and now that the chance to actually make a difference has come around, I don't want to screw anything up. We may never get a chance like this again. If we fail now, I don't think I'll ever get this motivation back."

Alphys took another glance at the phone.

"Sans," she began, pulling at the hem of her sleeve, "y-you're not just going to do that to your brother, are you?"

Sans had turned away from her before she even finished her sentence. Still, she continued on, trying to raise her voice enough so that she wasn't mumbling.

"I mean, U-Undyne was Papyrus' best friend." She looked down to her feet. "F-From what she told me, I think she was his only friend." When Sans remained silent, she figured it was okay to keep going. "Th-The human might have been f-friends with him; th-they called him a lot, I know, a-and they just left without even saying goodbye. A-And I'm sure he th-thinks that Undyne left too, am I right? I-If you just leave him like this, h-he'll start thinking everyone left him, a-and I don't think he'd really be a-all that wrong."

By the time she had finished, her voice had quieted down to a murmur, much to her displeasure. Despite this, Sans still wasn't reacting in the slightest, and she wondered if he had caught any of what she had said, or even cared for that matter.

It might have been the dim lighting of the room, but it wasn't until a few tense seconds later that she noticed just how hard the skeleton's shoulders were shaking. One of his hands were covering his mouth, and it was then that she finally heard the shuddering sobs he was trying to hide. With that realization, she felt as though she had been punched in the gut.

"S-Sans," she could barely hear herself with how quiet she had fallen. "I-I'm sorry."

Though she didn't think he'd heard her, he responded, back still facing her. "Don't do this to me, Alphys." His voice was breaking, despite his best efforts. "I know Paps is going to be all alone, but I have to do this." Another sob. "If we can get Gaster back, and if the time resets, then he won't even remember any of this."

It was obvious that he didn't even have himself convinced with that excuse, but Alphys was too afraid to say anything else. It was always like this. Any time she tried to help, she only went and made things worse. It had been the same with Mettaton, after he had left Napstablook to get a new body and become a star. Everything she said had only seemed to drive him further away from his cousin. It had happened before, and it would happen again it seemed; this time with Sans and his brother. She knew that fixing the timeline was important, but was it worth Sans abandoning his brother, right after everyone else already had?

She sighed, pulling harder on the hem of her sleeves. If she was being honest with herself, she didn't know the answer to that question. If everything Sans had told her was true, then they really didn't have the time to be screwing around. Fixing their timeline depended on them in that very moment. A reset would destroy the only chance they'd ever get.

A light shuffling brought her attention back to Sans, who had sat down in her desk chair. He was rubbing at his eye sockets, though he appeared to have mostly composed himself. The only thing that unnerved her was the way that his eye sockets had darkened, his pupils no longer visible. That, coupled with his ever straining grin, was not something she wanted to become accustomed to seeing.

"We should get working, huh?" was all he said. He wiped away the remaining tears from his eye sockets, swiveling the chair around to face Alphys' computer.

Alphys, uncertain if she even wanted to go through with this anymore after the skeleton's small breakdown, pulled up a chair beside him. He was right, they had work to do. They were going to retrieve Dr. Gaster from wherever he was and restore the timelines.

 **A/N** : No one ever tries to utilize Alphys in their fanfictions. It's a shame, since she's such a complex, interesting character. Obvious liberties were taken with Dr. Gaster. We know nothing about him, so it's inevitable. I haven't posted anything here in ages, so I apologize for any mistakes I make here. Would anyone be willing to help me out with the rating for this? I figured maybe K+, but Alphys' mentions of suicide have me worried. Should it be T instead?


	2. Chapter 2

6:15 AM _– SANS, YOU'RE NOT AT YOUR POST! WHERE ARE YOU?!_

6:16 AM _– YOU'RE NOT STILL IN BED, ARE YOU?! YOU WEREN'T THERE WHEN I CHECKED AN HOUR AGO!_

8:23 AM _– DOGARESSA SAYS THAT YOU STILL HAVEN'T SHOWED UP TO YOUR POST?_

3:03 PM _– SANS, RINKO SAID HE'LL FIRE YOU IF YOU KEEP SHOWING UP LATE_

3:03 PM _– OR NOT AT ALL IN THIS CASE_

3:03 PM _– HOW DO YOU EVEN SPELL HIS NAME?_

Papyrus threw his phone down on the couch after he was done with it, only to realize that that was something his lazybones brother would do, and instead opted to pick it back up and set it on the kitchen counter. He paced back and forth from the kitchen to the living room for a short amount of time, trying to think everything over. Where the heck was Sans? His brother was usually late to his post out in Snowdin Forest, sure, but today he never even showed up. He only had a nine hour shift today too, which really wasn't so bad compared to the usual shifts Rhyncho gave them.

He frowned slightly, or at least to the best of his ability, considering his lack of lips. After the Royal Guard had disbanded, the scaly bird-monster had shown up and taken over command of the sentry posts in the Snowdin area. He was huge and strong (though Papyrus would never admit that he was stronger than Undyne), and the dogs all seemed to like him for whatever reason, so no one ever complained about his little take over.

Unfortunately, he was kind of a jerk. At least to Papyrus and Sans he was. Sans because he was Sans, meaning that he never showed up to work (or actually did any work for that matter), and Papyrus because, well, he wasn't too sure. He tried his hardest, he really did, but nothing he did ever seemed to satisfy their new commander. Sans told him to just ignore it, saying that Rhyncho was just a really strict guy (some terrible bird or reptile pun usually following this explanation, of course). Still, Papyrus just didn't get it. What was he doing wrong? He definitely did more work than his brother did, yet he was certain that their new commander liked Sans more than he liked him.

He glanced back at his phone, checking to see if his brother had finally responded to him, but no luck. Getting increasingly irritated and upset, he plopped himself down onto the couch, turning on the TV. One of Mettaton's shows was playing, as was expected, though it was just a rerun of one of his older game shows. Figuring that there was nothing better for him to do until Sans decided to show his face, he curled up on the couch, accepting that he would be forced to watch this rerun. Not that he really minded; Mettaton was a great host after all. It was just that he'd much rather see something new at the moment. It would certainly help lift his spirits.

It was times like these that he really wished Undyne would hurry up and come back. Lots of monsters kept telling him that she had gone missing, but when he asked Sans about it, he told him that Undyne was just on vacation. He trusted his brother (most of the time), and was certain that all of those other monsters were just misinformed. His brother would know better than any of them anyways. Sans had followed the human around to watch over them the whole time they were there, and Papyrus knew for a fact that Undyne and the human had fought; the human had told him themself. _Why_ Undyne decided to go on vacation after fighting the human was beyond him, but he was kind of hoping she'd at least send him a postcard or something soon. While she was at it, maybe she could come back and take over for Rhyncho.

Undyne might have been a little brash, but at least she didn't make Papyrus feel like he was doing everything wrong all the time. She would always help him train to get better and prepare him for being a member of the Royal Guard, but Rhyncho? No way. If Papyrus did something even mildly "out of line" (according to Rhyncho), he got a massive scolding. Wasn't he the one who always had to scold Sans and the other sentries to keep them all from slacking off? So why would their new commander go specifically after him? He didn't understand it. If that reptilian-bird monster wanted him to change something, the least he could do would be to help him out.

He sighed, realizing that he wasn't even paying attention to the show that was on. He really missed Undyne. Sure, he had a whole ton of other friends he could talk to, like Sans… He frowned.

There was no need to wallow like this! If he wasn't careful, he was going to end up like his lazybones brother! Springing to his feet, Papyrus flipped off the television, running upstairs to check Sans' room. The room was locked as always, and knocking got him nowhere, as Sans was either asleep as always or not even there. Still, none of this was an issue. He ran back across the hall to his own room, grabbing the extra key in his drawers that Sans let him keep. He headed back and made his way into his brother's room, finding that Sans was not in there. Of course, Papyrus wasn't even all that surprised about that.

So Sans had to be at Grillby's, right? Or perhaps at the Ruins with Toriel? Those were the only two places his brother ever went nowadays. It was unusual for him to spend all morning at his favorite restaurant, missing an entire shift, but stranger things have happened. Either way, Papyrus was not going to just sit and complain to himself about Snowdin's new commander when he could be out doing something better with his brother. Maybe if he was lucky, he'd catch Sans at Toriel's and they could spend the rest of the day tending to the flowers in the Ruins.

His mind set, Papyrus fixed his scarf and threw his boots back on. Why he had taken them off in the first place was beyond him, since he should have figured that he'd end up leaving the house to go find his brother. Making sure to turn off the downstairs lights and lock the front door, Papyrus headed out into the bustling streets of Snowdin. It was snowing lightly out, though when he looked further out, there appeared to be a much heavier snowfall heading their way. Perhaps this would be the first snowstorm of the year, who knew? Either way, he had a brother to find, so off he went.

His first destination would be the obvious Grillby's, seeing as Sans was almost always there in the first place. Even if he wasn't there, he'd at least have the regular patrons there to confirm that yes, Sans was hanging out with Toriel that day.

He waved hi to a few residents of Snowdin as he walked his way down the road, though a majority of the monsters simply ignored him. They had busy lives they needed to attend to, he was sure of that, and they had no time to be waving back to any friendly skeletons they happened to pass by on their way. Perhaps he could take a note from them in order to finish his own tasks faster, but it felt wrong walking past anyone and _not_ giving them at least a quick wave. He wasn't even in that big of a hurry to find Sans anyways, seeing as he had all day and nothing better to do.

Seeing the giant grease-hole coming up, Papyrus couldn't decide if he wanted to smile or frown. For one, he'd be one step closer to finding Sans and figuring out why he was deciding to be lazier than usual that day, but on the other hand, it was the ever despised Grillby's. He could say that he liked a good portion of Grillby's regulars, and he'd for sure get to talk to some of them by being there, so there was another reason to smile he supposed. Slapping the usual grin on his face, he jogged the rest of the distance to the restaurant and strolled right on through the entranceway.

Some heads turned as he came through the door, though the patrons lost interest in him fairly quickly, the only monster greeting him being Lesser Dog. He gave a wave at the smallest of the dog guards as it turned back to its never-ending game of poker. With that accomplished, he gave a good look around the rest of the bar, finding a surprising lack of Sans hanging around there. Huh, he was sure that his brother would have been here. That only meant that Sans was at the much more preferred Ruins with Toriel, but it wouldn't hurt to ask around, as he had originally planned. He began by walking down to the back where Grillby was with a couple of regulars.

"So what are _you_ doing here?" sneered the sleazy bird monster that always accompanied Grillby at the bar top, "translating" whatever the flame monster had to say.

"Oh, well, I'm looking for Sans!" he answered, fully ignoring the bird's tone of voice. "Have you seen him around here recently?"

To his ever growing surprise, the bird scoffed, giving him an incredulous look. "You're kidding me, right?"

Wait, so was that a good reaction? "So, Sans was here?"

"No, he hasn't been here all day!" the bird gave him a dirty look. "Everyone's been waiting for him to show up, and instead we get you. It's quite the," it paused, apparently looking for the right word, "surprise, I guess."

"Oh," Papyrus deflated. Sans hadn't shown up at Grillby's even once today? Why? When he looked towards Grillby for confirmation of this, the flame monster merely nodded in agreement. So it was true then; Sans had miraculously not shown up there even once that day.

Becoming increasingly frustrated with the situation, he glanced back over to Lesser Dog, wondering if perhaps it had caught sight of his wayward brother during its shift earlier that day. Their shifts had overlapped that morning, so it was more than possible that the dog could have seen his brother. Then again, perhaps not, considering Sans' tendency to just teleport everywhere he went. It really did cause Papyrus more than his fair share of issues when he needed to find the guy.

He gave the bird monster a wave goodbye, though it had already gone back to the drink Grillby had handed to it. Walking by Lesser Dog, he contemplated questioning it about Sans, but considering that he wouldn't understand a word it said to him, he continued on.

Leaving the bar, he sighed in relief. He didn't enjoy being there more than he had to be. Yes, it was incredibly greasy, and he felt filthy just stepping into the place, but that wasn't the only issue he had. He always had the impression that he didn't particularly fit in there. Last time Sans had dragged him to Grillby's, the stocky skeleton had gotten a round of greetings, everyone glad to see the return of their favorite regular. It did not pass Papyrus' notice that not a single monster in that establishment aside from Lesser Dog had greeted him just a few moments ago. It could just be attributed to the fact that Papyrus was not a regular like Sans was, but he knew that the patrons of Grillby's at least knew of him. He went there to drag his brother away more times than he could count, Grillby thanking him for not letting Sans pass out at the bar top as had been known to happen on numerous occasions.

Well, he wasn't going to let that get him down. There was no need to associate with any of those monsters anyways. He had plenty of friends and acquaintances that he could hang out and talk with any time he wanted to, like Toriel! It was obvious that Sans had decided to spend his entire day hanging out with the former queen, and he doubted they would mind if his younger brother decided to come join them. Yes, it was odd that Sans would neglect to inform him of any of this, or just outright avoid making it to his shift for sentry duty, but perhaps his laziness was just reaching an all-time low.

He frowned, stopping in his tracks halfway across the bridge leading out of Snowdin. At this rate, Rhyncho really _was_ going to fire his brother. There was no way Papyrus could allow that to happen, remembering just how bad Sans' laziness had gotten before he convinced him to get the sentry job in the first place. The thought of his brother getting _that_ bad once again sent shivers down his spine. Sans needed to be happy, and he definitely wasn't happy when left to laze around in a depressed stupor. Once he reached the Ruins, he'd have to talk with his brother about keeping his job. Nagging him would get them nowhere; experience told him that, but perhaps Toriel could help with talking some sense into his brother.

With that in mind, he continued on. It was quite the walk from Snowdin to the Ruins, so it was best to keep moving. Honestly, while he believed Sans' teleporting to be the laziest ability he could possibly have, it would come in handy for situations where he was impatient like this. A long walk would likely do him some good though, considering how quickly he was finding himself falling into depressed stupors not unlike his brother's. As he told Sans time and time again, keeping himself busy was a good way to stop himself from thinking like that, so yes, a walk would do him good.

Plastering a grin back on his face, he leaped over one of the spike puzzles found just after Lesser Dog's sentry post. So far none of the puzzles appeared to be needing recalibrating, so no one had come through this area recently. Perhaps that was good, though? After everything that had happened, Papyrus didn't know if he wanted another human to come through the area. Rhyncho had informed him in a not-so-friendly manner that it was expected for the sentries to kill any human on sight and take their soul to the barrier in New Home. While initially he hadn't believed such a thing, he found from the Dogi couple and a few other residents of Snowdin that this was, in fact, what was expected from _all_ monsters in the Underground now.

He didn't think he could kill a human. He didn't even know if he could bring himself to _hurt_ a human let alone kill one. The one that had made friends with him and left recently had been so nice, and he knew that all of the other humans above ground had the potential to be just as nice. They all had the right to leave and go back to their homes, just as the last human did, didn't they? While he had the slight suspicion that things had always been this way, he didn't think that they had always been this bad. Maybe everyone was confused without King Asgore being around to lead them. This was another issue he supposed he wanted to talk with Sans and Toriel about. If anyone would know anything about this, it would certainly be them.

Snow was beginning to fall in thick patches as he neared Snowdin Forest, though it wouldn't be much of a bother to him with the trees to block most of it. If he had to head back home anytime soon he might have a problem, but he was sure Toriel would be fine with letting him and Sans stay over in the Ruins with her. Otherwise, with the snow falling as it was, most of the icy patches on the way back would be covered up, and Papyrus knew he had a bad history with slipping and falling over on them (much to Sans' amusement).

Considering he had nothing to worry about for today, he moved on his way through the forest, ignoring the patches of snow that fell through regardless of the trees above. Many thoughts went through his head as he neared the door leading to the Ruins. Would Toriel bake another one of those pies that Sans loved so much? Would she continue helping him learn to cook? Would he get to see Flowey?

His grin ever widening, he found himself becoming increasingly excited to visit the former queen. Since Rhyncho had begun handing out longer shifts to each of the sentries in Snowdin, neither Papyrus nor Sans had been able to find time to visit Toriel. Though, if he was being honest with himself, Sans probably found time during one of his many "breaks". So it was more likely that only Papyrus hadn't had the time to visit her. That thought only caused his grin to grow even further. It would be fun seeing her again.

The door came into sight within no time, snow already piling up against the base of it. He reached down to grab his phone so he could check to see if he had made good time, but it then occurred to him that he had left it back home on the kitchen counter. Of all things not to grab on the way out, he had to forget his phone. Of course, it wasn't like anyone was going to call or text him anytime soon. No one had bothered with contacting him since the human had left a little over a year ago. Sans always just appeared when he needed to speak with him, even if Papyrus texted him in the first place. Who else would bother contacting him?

Snapping himself out of that train of thought—for what, the third, fourth time that day?—he reminded himself that he knew plenty of monsters who wanted to talk with him; monsters who never had any need nor want to use their phones to do so, obviously. Before he could fall back into that ever dreaded line of misery, he rapped a few times on the door before him. Either Toriel or Sans would answer in no time, and then they could all have a good time hanging out with each other.

It took a few moments longer than Papyrus had expected, but before he knew it someone was calling from the other side.

"Hello?" questioned the feminine voice, muffled from the stone doorway that remained firmly shut. Strange; why didn't she just open the door like usual?

"Hi Toriel!" he responded. "It's me!"

Her voice became clearer as the door opened ever so slightly.

"Oh, hello Papyrus, dear," Toriel greeted, peeking out from the crack in the doorway she made. If he didn't know any better, he'd say that her voice sounded almost timid, but Toriel was never like that around him, was she?

"Is Sans here? I've been looking everywhere for him!" Papyrus continued, deciding to ignore her tone of voice, just as he had done not too long ago with the bird monster from Grillby's.

"Sans? No, I haven't seen him since the last time you two came to visit.

Papyrus felt his grin falter. Sans wasn't here either?

"Oh," was his only response, as lame as it sounded. "Are…are you sure?"

The former queen gave a hurried glance behind her, checking on something Papyrus could not see from beyond her place in the Ruins. As her attention returned to him, her face took on a saddened look.

"No, I'm sorry. Listen, I should probably go. Have you tried checking Grillby's? You know how much he loves going there."

He sighed, his grin gone once more. "That was the first place I checked. I—"

"I'm sorry Papyrus, but I've got some work I need to do. I hope you find Sans."

Did Toriel just interrupt him? His eye sockets widened in shock. Now that he thought about it, her tone was getting increasingly rushed, as if she was eager to get back to whatever it was she had been doing earlier.

"Toriel, wait. Can I come in? Maybe I can help!" he tried to stop her as the door began to close once more.

"No, dear. I'm sorry. I have to go. It was nice seeing you! I hope we can talk longer next time!" she spouted out, shutting and presumably locking the door behind her.

Papyrus felt his jaw hang open. That was…bizarre. Not once had he ever seen Toriel act in such a way. Every time he and Sans had come to visit, the former queen would welcome them both with open arms. Outright rejecting them? Certainly not. Realizing that he was still staring at the door, he slowly turned around, facing the forest pathway he and his brother had made to help with traversing between Snowdin and the Ruins. What was going on that day?

After some time, he found himself walking back out of the forest. He didn't remember when he even began walking, but he found himself nearing Doggo's sentry post on the edge of the woods nevertheless. The dog in question was sitting behind his post, readying a new dog treat. As Papyrus walked by, stuck in the equivalent of a dazed stupor, the dog gave him a glance, but turned back to his treat after seeing who had been walking by.

After fully exiting the forest, he put a gloved hand to his skull. He supposed he could worry about Toriel later. If she was busy, then that was her business. Papyrus could relate to her situation if he was understanding it properly, and knew what it was like to have so much work to do in so little time. Right now, he was more worried about his brother. Just where was Sans? This was too unusual a situation for him, considering Sans could only ever be found in his room, at Grillby's, or at Toriel's. Where could he possibly be if not at those three places? His lab in the basement, perhaps?

The thought held promise, considering there was nowhere else he could think of, but since when had his brother actually gone down there in recent times? Sighing, he resigned himself to heading all the way back home to check the basement. If he was lucky, his brother would either have returned home by then or responded to his phone. Not that he _ever_ responded to his texts, but at that point Papyrus was hanging on by a thread idea-wise.

So lost in thought, he paid no attention to where he was stepping, feeling his foot slip out from beneath him as he took his next step. Training with Undyne had at least prepared him for something like this, as his reflexes allowed him to catch himself before fully slamming onto the ice below. Sitting in the ever growing amount of snow on the ground, he could at least take peace in that fact that no one was around to see him slip like that. Leaning back on his forearms, he gazed up at the snowfall, unrelenting as it continued its way down in large clumps. It was going to be a long way back if he couldn't keep his mind on not slipping every five seconds. It was difficult when he was so desperate to figure out where his brother was.

What did it matter anyways? The thought came to him as he attempted to climb his way back to his feet. It was at most four or five in the afternoon, and Sans was allowed to do whatever he wanted with his life. It's not like he needed his younger brother hunting him down just because, what? He was feeling lonely? That was ridiculous and he knew it. His routine had been disturbed and he wanted to fix it and make sure Sans actually went to work the next day, that was all.

With that settled, he walked the rest of the way home, minding the hidden ice patches beneath the new snow accumulating around him. It was rather uneventful, with most monsters likely having decided to remain in their homes rather than brave the oncoming snowstorm. He found himself back in town in no time, entering his house and running back up to Sans' room. He knew that his brother kept the basement key in his top dresser drawer. If his brother was in his lab, then the key would be gone.

Opening the drawer, Papyrus had to admit that he wasn't very surprised to see the key still in its place. Sans hadn't been anywhere else that day, so why should he be in his lab? He supposed he should check, just in case his brother had teleported his way into the basement, but even then he had very little hope of actually locating him at this point. Snatching the key out of the drawer, he headed back downstairs, stopping to check his phone as he passed the kitchen. Nope, no missed calls or texts. Not much of a shock either.

Heading outside and moving to the back of the house, he unlocked the basement door and made his way down. Upon first opening the door, he found the room to be in a dark, murky state, giving off the obvious impression that his brother probably wasn't there. Still, he turned the lights on and took a look around. The weird machine was still sitting in the corner, covered by the worn blanket that looked like it hadn't been removed in years. He never questioned it before, and he wasn't going to begin questioning it now.

While Papyrus very rarely came down to his brother's lab, he at least had a general idea of what was located down there and what everything looked like, even if he had next to no idea of what any of it did. The first thing he noticed was that Sans' files were all gone; those weird ones with all the symbols that he couldn't understand on them. The device usually connected to the computer monitor was also missing. Of course, none of this actually meant a thing to him, as Sans could have simply removed all of those things ages ago. Papyrus couldn't actually remember the last time he had come down to this place, so who knew what Sans had done down there since then.

Ten minutes later found Papyrus sitting back on the couch finishing a rerun of the same game show as earlier. The lab had been locked back up, the key returned to Sans' room, and the room itself relocked. His little adventure that day had gained him nothing. He still knew not of Sans' whereabouts, and all he actually knew about anything was that Toriel was acting strangely. That left him with more questions than answers, much to his chagrin.

Well, Sans would show up eventually; he always did. Papyrus would make dinner, Sans would tell him that he already ate at Grillby's, Papyrus would scold him for missing work, and then everything would go back to normal. He kept telling himself this, yet he still felt as though he couldn't find a reason to grin once more. Sans never deviated from the norm after all, which made Papyrus uneasy. He brought his attention back to the television as another rerun began to play. After everything, he knew that he could trust Sans. There was nothing to worry about. His brother was just being extra odd today. All he had to do was keep himself busy for a few more hours and his brother would be back. No big deal.

 **A/N** : A very slow chapter, here. I realize that I have problems pacing things, which is actually one of the issues I try to address in the other Undertale fic I wrote that I'll be posting soon. I tried to hasten the pace in that one so it doesn't feel like it's crawling along, but it feels kinda fast anyways. I'll see what happens once I actually post it. It's very experimental for me, and hopefully people like it.


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